1. Technical Field
The invention relates to loudspeaker systems, and more particularly is directed to loudspeaker system intended for high efficiency, bass system for either out of doors or large enclosed space applications.
2. Description of the Problem
A great part of the usefulness of a loudspeaker system depends upon the effectiveness of the enclosure in which the sound transducers are housed. Effectiveness as a term must be understood in a somewhat relative sense, since a sound system may be dedicated to a particular environment, or it be intended to be mobile, it may be intended to reproduce low frequency sound or high frequency sound, it may be intended for high fidelity reproduction of Baroque music or it may be intended for extremely high efficiency radiation of voice in a stadium setting where some distortion is tolerable as long as intelligibility is preserved. The system should also deliver or direct the sound reproduced to the intended audience.
Accordingly, efficiency, as the term is used herein, should be understood to comprehend increased sound energy density in watt-seconds per cubic meters at desired locations and at the desired frequencies without increases in electrical power input to the sound transducers in the loudspeaker system.
It is well known that sound energy density may be increased in particular areas by increasing the directivity of a loudspeaker system. This may involve confining the sound energy to a beam, potentially in both vertical and horizontal planes, and than controlling the width of the beam. Directivity is achieved in a number of ways including phase control over doublets of radiators, arrays of radiators, baffles, enclosures and horn loading, etc. Horns and bass reflex enclosures are particularly favored, with horns providing the higher efficiencies, typically at the cost of distortion of the sound. Of course both horns and enclosures come in a baffling variety of forms. The development of neither horns nor bass reflex enclosures is exhausted, particularly with respect to the positioning of multiple element transducers on the enclosure and use of electronics to control the relative phase in sound reproduction between the transducers.